Method of making venturi tubes.



H. C. KIRK.

METHOD OF MAKING VENTURI TUBES.

APPLICATION FILED JUNE H, 1917.

Patented Nov. 6, 191?.

awe-01421 1 1111mm 0. mm, OFIRO'LANDPARK, menu];

.METHODaOF-MAKING VENYIIiRI mums.

To all whom it may. concern:

' Be it known that I, HENRY C. KIRK, a citizen offlthe United States of America, re siding at Roland Park, Baltimore county, Maryland, have invented certain new and useful Improvementsinhlethods of Making Venturi Tubes, specification.

AVenturi tube, as the word is used in the mechanical arts, is a tube having "its di-' ameter reduced intermediately. The obvious method of making such Venturi tubes is by spinning seamless tubing but on account of the ex'cessive demand for such seamless tubing, it is almost impossible to obtain it. in quantities and at prices commensurate with the production of Ventu-ri tubes to meet the demand. The ll'olle'd or seamed tubing can, however,bejnuch more easily obtained as its manufacture from sheet metal requires less elaborate apparatus and plant. The seamed tubing cannot, however, be spun to advantage as the cmcumferential stress necessary to spin tubing of sutficiently heavy grades generally opens the scams or breaks them suificiently to cause leaks and the lighter tubing which can be spun is not considered sufiiciently durable and substantial for this work. This practical difiiculty has proved important and has only been overcome at considerable expense of time, money and effort used in the evolution of a method of treating tubing in the production of these Venturi tubes which is applicable to the rolled and seamed tubes as well as to the seamless tubes. This method, broadly stated, consists in reducing the diameter of the tube at a point intermediate of its length by forming plaits, folds or fins in the walls of the tube. These preferably are radially disposed, though this is not essential to the broad conception of the invention but when so placed they have a very useful function as reinforcing members at the otherwise weakened portions of the tube. The operation is accomplished by means of dies shaped to the external form of the venturi and having between the operative surfaces at the sides spaces which receive and form the plaits or fins. The dies, and hence the fins or plaits, may be of any desired number.

In the accompanying drawing I have illustrated the invention so far as it is capable of being shown.

Specification of Lettersflate'nt.

of which the following is of seamed tubing JFig. 2 71s an elevation (of a siinilar piece within f du ring fthe formation of the vein.

turl;

Fig. 5 is. a longitudinal, centralJs'ectionof the same partly broken faway'for convenience;

Fig. 6.158 a .plan;,offo"ne cf't'hefdies llookiifig a y the operative surface g is Fig. 6;

,lfig. 8..is. a;-section onltheilineigiisfinFig.

6 and r Fig. ,9. is anelevation ofithe .tvrmdiesand v the .mandrel in operation, a portion of the dies being cut away and shown in section to disclose the mandrel and tube being operated upon, the latter being in section.

Referring to the drawings by numerals: The method consists in treating sheet metal tubing 1, which may be either seamed or seamless but is shown as a seamed tube, forming in the tube a venturi 2 by plaiting or folding the side walls of the tube where I the venturi is located and thus reducingthe diameter of the internal passage, forming ribs or plaits 3, preferably radially disposed as shown. In the practice of the method I use dies 4 of any convenient number having their operative surfaces hollowed out at 5 in corresponding sections of the external form of the tube at the venturi. These hollows also include spaces 6 formed by offsetting a portion of the adjacent surfaces of the dies and corresponding to the fins or plaits 3. These are adapted to receive and form folds of metal thrown out by the reduction of the diameter of the tube. These folds as already stated, have a reinforcing function at a point where the tube would otherwise be weakened. To support the tube from within 'in order to prevent crushing of the tube, and make the reduced portion uniform, I find it convenient to use a mandrel 8, shaped to the inside of the venturi and formed in two sections joined at 9 so that the mandrel may berempved' after the operation.

fFigure .1 is"; an elevation of Ta siidrgpieee '7 its secfien on jlthejline "7., the."

To center the sections I preferably pro-- vide a central pin or stud 10 on one sect-ion which cooperates with and enters a corresponding opening 11 in the other section.

In Fig. 9 I have shown the dies in the die press 12 provided with suitable handles 13 for the mandrels and abutments 14: for positioning the tube relatively to the mandrels, a stationary abutment 15 also being provided at one end to engage the positioning member 16. This latter part of the apparatus relating to the press, handles, abutments and so forth may be provided by the designer and is not a part of the invention. The operation consists in placing the tube containing the mandrel in the hollow of one die and forcing the other die down on it reducing the diameter of the tube a by forming plaits which conform to the spaces 6 in the dies at the same time the dies and the mandrel control the form of the venfrom sheet metal tubing which consists in plaiting the side walls of the tube at a point intermediate of its length thus reducing the diameter and taking up the surplus metal, at the same time shaping the walls of the tube externally according to the desired form of the venturi.

2. A method of making a Venturi tube from sheet metal tubing which consists in plaiting the side walls of the tube at a point intermediate of its length thus reducing the diameter and taking up the surplus metal at the same time shaping the walls of the tube externally and internally according to the desired form of the venturi.

3. VA method of making a Venturi tube from sheet metal tubing which consists in forming radial plaits in the side walls of the tube at a point intermediate of its length thus reducing the diameter and taking up the surplus metal, at the same time shaping the walls of the tube according to the de sired form of the venturi.

Signed by me at Baltimore Maryland,

-this 9th day of June, 1917.

HENRY c. KiRK.

WVitnesses:

ZELLA KUHN, PORTER H. FLAoE'r'r.

Cable: 01 this patent may be obtained for five cents each, by addressing the Commissioner of Patent-l,

Washington, D. 0. 

